chickadee » generalized-arrays » array-interval

Returns the "interval" of a given array. The current interval of a given array is the range of multi-dimensional indices that are valid for that array object. It is not always the case that the interval starts at the default (zero) multi-index. For example:

 
(import generalized-arrays)

(define a
  (make-array vector-storage-class
              #(3 3)
              0))

(test "Interval of array a"
      (make-interval #(0 0) #(3 3))
      (array-interval a))

(define b
  (array-slice a #(1 1) #(2 2)))

(test "Interval of array b"
      (make-interval #(1 1) #(2 2))
      (array-interval b))

In the above example, the array b is a slice of array a, from #(1 1) to #(2 2), so while b shares the same storage-object as a, the interval of b is smaller than that of a.

array-interval is meant to be used as a low-level mechanism for being able to work with slices over a shared storage-object. In most cases, you'll want to use array-shape to get the semantic interval over the array, rather than array-interval.